The quarterback, who started the season as the team's third-stringer, will start his second game for the AFC South side tomorrow.
The head coach told reporters: "I think he gets more comfortable every day, but at the same time, it's a new game plan, it's a new team we're playing.
"You do start from scratch each week, but I think he's getting more comfortable in the huddle and more comfortable with his timing and stuff with our receivers. I think he's been very accurate this week.
"This kid's working his tail off and trying to do everything to give his football team a chance to win. Just impressed with how he's working. He's ready to good. He's had a good week. He's worked real hard. We've got to try and keep him in the best position we can keep him in."
The Texans play the Indianapolis Colts tomorrow.